Known pet toilets for treating the excreta of pets such as cats and dogs include those disclosed in JP 7-67489A and JP 2003-180182A, in which a toilet box is partitioned into upper and lower compartments by a porous member (drainboard), with an excreta treating material put in the upper compartment and a urine absorbent member is made of an absorbent polymer, plant fiber, pulp, etc. set in the lower compartment.
According to these pet toilet systems, liquid waste discharged by a pet is allowed to quickly pass the excreta treating material placed in the upper compartment, drop through the drain holes of the drainboard, and be positively absorbed by an urine absorbent member, such as a urine absorbing mat, laid in the lower compartment of the toilet box. The urine absorbent member having absorbed urine must be replaced periodically. For the purpose of facilitating the replacement, JP Utility Model 61-22461A discloses a system in which the lower compartment of the toilet box where the urine absorbent member is placed is designed to be pulled out like a drawer.